Question 1

A piece of zinc metal was added to an aqueous solution of lead(II) nitrate. After some time it was observed that the zinc metal appeared to fall apart and a solid had accumulated at the bottom of the reaction vessel.Select the balanced chemical equation for this reaction. A) Zn(s) + Pb(NO₃)₂(aq) $\rarr$ Pb(s) + Zn(NO₃)₂(aq) B) 2Zn(s) + Pb(NO₃)₂(aq) $\rarr$ Pb(s) + 2Zn(NO₃)₂(aq) C) Zn(s) + 2Pb(NO₃)₂(aq) $\rarr$ Pb(s) + 2Zn(NO₃)₂(aq) D) Zn(s) + 3Pb(NO₃)₂(aq) $\rarr$ 3Pb(s) + 3Zn(NO₃)₂(aq) E) None of the above

Accepted Answer

The correct balanced chemical equation for the reaction between zinc metal and aqueous lead(II) nitrate, resulting in the formation of solid lead and aqueous zinc nitrate, is represented by option A. This follows the single replacement reaction principle where zinc displaces lead from its nitrate compound.

Question 2

If 145 grams of potassium nitrate were added to water to make 1,500 mL of solution. What would the molarity of the resulting solution be
A) 0.956 M
B) 0.856 M
C) 0.756 M
D) 0.656 M
E) None of the above

Accepted Answer

The molarity (M) of a solution is calculated using the formula M = moles of solute / liters of solution. Potassium nitrate (KNO3) has a molar mass of approximately 101.1 g/mol. Therefore, 145 grams of KNO3 is equivalent to 145 g / 101.1 g/mol = 1.434 moles. The volume of the solution is 1,500 mL, which is 1.5 liters. Thus, the molarity of the solution is 1.434 moles / 1.5 L = 0.956 M.

Question 3

A piece of copper metal was added to an aqueous solution of silver nitrate, and within a few minutes it was observed that a grey crystalline solid formed on surface of the copper. The solution turned a blue color characteristic of copper(II) ions. Select the correct net ionic equation for this reaction. A) Cu(s) + Ag⁺(aq) $\rarr$ Cu²⁺(aq) + Ag(s) B) Cu(s) + 2Ag⁺(aq) $\rarr$ Cu²⁺(aq) + 2Ag(s) C) Cu(aq) + 2Ag⁺(aq) $\rarr$ Cu²⁺(aq) + 2Ag(aq) D) 2Cu(s) + Ag⁺(aq) $\rarr$ 2Cu²⁺(aq) + Ag(s) E) None of the above

Accepted Answer

The initial reaction is: 
Cu(s) + 2AgNO3(aq) -> Cu(NO3)2(aq) + 2Ag(s)
The net ionic equation is obtained by only showing the species that are directly involved in the reaction:
Cu(s) + 2Ag+(aq) -> Cu2+(aq) + 2Ag(s)
The grey crystalline solid that formed on the surface of the copper is likely Cu2O, which is not included in any of the answer choices.

Question 4

The following two equations show both the correct balanced molecular and net ionic equations for the reaction that would occur between Al(s) and Co(NO₃)₂(aq).Molecular equation: 2Al(s) + 3Co(NO₃)₂(aq) $\rarr$2Al(NO₃)₃(aq) + 3Co(s) Net ionic equation: 2Al(s) + Co²⁺(aq) $\rarr$ 2Al³⁺(aq) + Co(s)

Accepted Answer

The provided equations seem to contain formatting or encoding errors, making it difficult to accurately assess the chemical reaction described. The symbols and formatting do not correspond to standard chemical notation.

Question 5

During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with 1.0 M NaOH; 40. mL of the base were required to neutralize the sample. What is the molarity of the acid solution
A) 1.0 M
B) 2.0 M
C) 3.0 M
D) 4.0 M
E) None of the above

Accepted Answer

The answer of During a titration the following data were...

Question 6

During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with 1.0 M NaOH; 40. mL of the base were required to neutralize the sample. How many moles of acid are present in 2.0 liters of this unknown solution
A) 6.0 moles
B) 7.0 moles
C) 8.0 moles
D) 9.0 moles
E) None of the above

Accepted Answer

First we need to find the number of moles of NaOH used in the titration:

1.0 mol NaOH = 1 L NaOH

Therefore:

40 mL NaOH x (1 L / 1000 mL) x (1 mol NaOH / 1 L) = 0.04 mol NaOH

Since the acid is monoprotic (meaning it donates only one proton/H+), the number of moles of acid is equal to the number of moles of NaOH used in the titration:

0.04 mol H+ = 0.04 mol acid

Now we can calculate the concentration of the unknown acid solution:

0.04 mol / 0.01 L = 4 mol/L

Finally, to find the number of moles in 2 liters of this solution:

4 mol/L x 2 L = 8 mol

Therefore, the answer is C) 8.0 moles.

Question 7

Shown here is the balanced molecular equation that would occur between CaCl₂(aq) and Na₂CO₃(aq). Which of the following is the balanced net ionic equation Molecular equation: CaCl₂(aq) + Na₂CO₃(aq) $\rarr$CaCO₃(s) + 2NaCl(aq) A) Net ionic equation: Ca²⁺(aq) + 2 Cl^-(aq) $\rarr$ CaCO₃(s) B) Net ionic equation: Ca²⁺(aq) + CO₃^2-(aq) $\rarr$ Ca²⁺⁽aq) + CO₃(aq) C) Net ionic equation: Ca²⁺(aq) + CO₃^2-(aq) $\rarr$ CaCO₃(s) D) Net ionic equation: 2Na⁺(aq) + CO₃^2-(aq) $\rarr$Na₂CO₃(s) E) None of the above

Accepted Answer

The net ionic equation only includes the ions that react to form the solid CaCO₃. The spectator ions (Na+ and Cl-) are not included in the net ionic equation because they do not participate in the reaction. Therefore, option C is the best choice as it shows only the necessary ions involved in the reaction.

Question 8

Shown here is the balanced molecular equation for the reaction that would occur between CuCl₂(aq) and Pb(s). Which of the following, if any, shows the correctly balanced net ionic equation Molecular equation: CuCl₂(aq) + Pb(s) $\rarr$ Cu(s) + PbCl₂(s) A) Net ionic equation: Cu²⁺(aq) + 2Cl^-(aq) + Pb(s) $\rarr$ Cu(s) + Pb²⁺ (aq) + 2 Cl^-(aq) B) Net ionic equation: 2Cu²⁺(aq) + 2Cl^-(aq) + Pb(s) $\rarr$ 2Cu(s) + PbCl₂(s) C)Net ionic equation: Cu²⁺(aq) + Pb(s) $\rarr$ Cu(s) + Pb²⁺(aq) D) Net ionic equation: Cu²⁺(aq) + 2Cl^-(aq) + Pb(s) $\rarr$ Cu(s) + PbCl₂(s) E) None of the above

Accepted Answer

The net ionic equation should only include the reactants and products that are directly involved in the chemical reaction, meaning any spectator ions should be eliminated. In this case, the spectator ions are the Cl- and Pb2+ ions, which do not participate in the reaction. Thus, the net ionic equation should be:
Cu2+(aq) + Pb(s) → Cu(s) + Pb2+(aq)
However, since CuCl2 is a soluble salt, it will dissociate in water and form Cu2+ and Cl- ions. Thus, the complete net ionic equation is:
Cu2+(aq) + 2Cl-(aq) + Pb(s) → Cu(s) + PbCl2(s)
Choice D is the correct net ionic equation, which eliminates the spectator ions and correctly includes the products Cu and PbCl2.

Question 9

A piece of lead metal was added to an aqueous solution of copper(II) nitrate, and within a few minutes it was observed that the lead turned black and crumbled. The characteristic blue solution of copper (II) ions had faded. (NOTE: Lead forms a 2+ ion when it reacts.) Select the balanced chemical equation for this reaction. A) Pb(s) + CuNO₃(aq) $\rarr$ Cu(s) + Pb(NO₃)₂(aq) B) 2Pb(s) + Cu(NO₃)₂(aq) $\rarr$ Cu(s) + 2Pb(NO₃)₂(aq) C) Pb(s) + Cu(NO₃)₂(aq) $\rarr$ 2 Cu(s) + Pb(NO₃)₂(aq) D) Pb(s) + Cu(NO₃)₂(aq) $\rarr$ Cu(s) + Pb(NO₃)₂(aq) E) None of the above

Accepted Answer

The balanced chemical equation for the reaction is Pb(s) + Cu(NO₃)₂(aq) $\rarr$ Cu(s) + Pb(NO₃)₂(aq), where lead displaces copper from copper(II) nitrate, forming lead(II) nitrate and copper metal.

Question 10

Which substance is acting as a Brønsted acid in the following reaction HSO₄^- + NH₄⁺ $\rarr$ H₂SO₄ + NH₃ A) HSO₄^- B) NH₄⁺ C) H₂SO₄ D) NH₃ E) Both HSO₄^- and NH₄⁺

Accepted Answer

NH₄⁺ donates a proton to form NH₃, acting as a Brønsted acid.

Question 11

The following net ionic equation correctly shows the result when a piece of zinc metal is added to an aqueous solution of lead(II) nitrate. After some time it was observed that the zinc metal appeared to fall apart and a solid had accumulated at the bottom of the reaction vessel. Zn(s) + Pb²⁺(aq) $\rarr$Zn²⁺(aq) + Pb(s)

Accepted Answer

The net ionic equation correctly represents the redox reaction where zinc metal displaces lead ions from the solution, forming zinc ions and solid lead.

Question 12

The two reactions shown here represent balanced molecular and net ionic reactions for the acid-base neutralization reaction between H₃PO₄(aq) and Ba(OH)₂(aq).Molecular equation: 2H₃PO₄(aq) + 3Ba(OH)₂(aq) $\rarr$Ba₃(PO₄)₂(s) + 6H₂O(l) Net ionic equation: 2H₃PO₄(aq) + 3Ba²⁺(aq) + 6OH^-(aq) $\rarr$ Ba₃(PO₄)₂(s) + 6H₂O(l)

Accepted Answer

Both the molecular equation and the net ionic equation are balanced and represent the acid-base neutralization reaction between H₃PO₄(aq) and Ba(OH)₂(aq).

Question 13

During a titration the following data were collected. A 50.0 mL portion of an HCl solution was titrated with 0.500 M NaOH; 200. mL of the base was required to neutralize the sample. How many grams of HCl are present in 500. mL of this acid solution
A) 46.5 g
B) 36.5 g
C) 26.5 g
D) 16.5 g
E) None of the above

Accepted Answer

First, calculate the number of moles of NaOH used in the titration:
0.500 mol/L x 0.200 L = 0.100 mol NaOH

Since the reaction between HCl and NaOH is a 1:1 ratio, there are also 0.100 mol of HCl in the 50.0 mL sample used in the titration.

To calculate the concentration of HCl in the original solution, use the formula:
moles of solute/volume of solution in liters

0.100 mol HCl/0.050 L = 2.00 M HCl

Finally, to calculate the grams of HCl in 500. mL of the solution:
2.00 mol/L x 0.500 L = 1.00 mol HCl
1.00 mol HCl x 36.5 g/mol = 36.5 g

Therefore, the best choice is B) 36.5 g.

Question 14

The following experiments were carried out and observations recorded.
Expt. #1: copper metal was added to an aqueous solution of silver nitrate Observation: The copper become coated with a substance.
Expt. #2: lead metal was added to an aqueous solution of copper(II) nitrate
Observation: The lead turned black and crumbled.
Expt. #3: zinc metal was added to an aqueous solution of lead(II) nitrate
Observation: The zinc appeared to fall apart.Which, if any, of the following properly ranks the metals from most active to least active.
A) Most active Pb, next most active Zn, next most active Cu, least active Ag
B) Most active Zn, next most active Ag, next most active Cu, least active Pb
C) Most active Zn, next most active Cu, next most active Pb, least active Ag
D) Most active Zn, next most active Pb, next most active Cu, least active Ag
E) None of the above

Accepted Answer

The reactivity series of metals is based on their ability to displace ions in aqueous solutions of other metals. In Experiment 1, copper is less reactive than silver and therefore cannot displace the silver ions from the aqueous solution. Instead, a redox reaction occurs, with the copper atoms losing electrons to the silver ions and becoming coated with silver. In Experiment 2, lead is more reactive than copper and can displace the copper ions from the aqueous solution, forming solid lead(II) nitrate and copper metal. In Experiment 3, zinc is more reactive than lead and can displace the lead ions from the aqueous solution, forming solid zinc nitrate and lead metal. Therefore, the order of reactivity from most to least active is Zn > Pb > Cu > Ag, which is represented in choice D.

Question 15

H₂O is acting as a Brønsted acid in the following reaction. NH₃ + H₂O $\rarr$NH₄⁺ + OH^-

Accepted Answer

In the given reaction, HS1U1B12S1U1B0O donates a proton to NHS1U1B13S1U1B0 to form NHS1U1B14S1U1B0S1U1P1, indicating that it is acting as a Brønsted acid.

Question 16

The following net ionic equation correctly shows the result of this experiment: A piece of lead metal was added to an aqueous solution of copper(II) nitrate, and within a few minutes it was observed that the lead turned black and crumbled. The characteristic blue solution of copper(II) ions had faded. (NOTE: Lead forms a 2+ ion when it reacts.) Pb(s) + Cu²⁺(aq) $\rarr$ Pb²⁺(aq) + Cu(s)

Accepted Answer

The net ionic equation correctly represents the reaction between lead metal and copper(II) nitrate, which forms lead sulfide and copper metal. The observed black color and crumbling of the lead is due to the formation of insoluble lead sulfide. The fading of the blue color of copper(II) ions indicates that copper has been reduced to its elemental form.

Question 17

What volume of concentrated nitric acid (15.0 M) is required to make 100. mL of a 3.0 M nitric acid solution
A) 20. mL
B) 30. mL
C) 40. mL
D) 50. mL
E) None of the above

Accepted Answer

M1V1 = M2V215.0 M * V1 = 3.0 M * 100. mLV1 = 20. mL

Question 18

The solubility of Ba(NO₃)₂ is 130.5 grams per liter at 0^$\circ$C. How many moles of dissolved salt are present in 4.0 liters of a saturated solution of Ba(NO₃)₂ at 0ºC A) 1.0 moles B) 2.0 moles C) 3.0 moles D) 4.0 moles E) None of the above

Accepted Answer

First, we need to convert the given solubility from grams per liter to moles per liter: Molar mass of Ba(NO₃)₂ = 663.83 g/mol 130.5 g/L ÷ 663.83 g/mol = 0.1964 mol/L Next, we can use this concentration to calculate the number of moles in 4.0 liters: 0.1964 mol/L x 4.0 L = 0.7856 moles Therefore, the answer is approximately 0.8 moles, which corresponds to choice B (2.0 moles rounded to the nearest whole number).

Question 19

What is the molar concentration of chloride ions in a solution prepared by mixing 100. mL of 2.0 M KCl with 50. mL of a 1.5 M CaCl₂ solution A) 5.3 M B) 4.3 M C) 3.3 M D) 2.3 M E) None of the above

Accepted Answer

The answer of What is the molar concentration of chloride...

Question 20

A piece of copper metal was added to an aqueous solution of silver nitrate, and within a few minutes it was observed that a grey crystalline solid formed on surface of the copper. The solution turned a blue color characteristic of copper(II) ions. Select the correct balanced chemical equation for this reaction. A) Cu(s) + AgNO₃(aq) $\rarr$Ag(s) + Cu(NO₃)₂(aq) B) Cu(s)₂ + AgNO₃(aq) $\rarr$ Ag(s) + Cu(NO₃)₂(aq) C) Cu(s) + 2AgNO₃(aq) $\rarr$ 2Ag(s) + Cu(NO₃)₂(aq) D) 2Cu(s) + 2AgNO₃(aq) $\rarr$2Ag(s) + 2Cu(NO₃)₂(aq) E) None of the above

Accepted Answer

The balanced chemical equation for the reaction should have the same number of atoms of each element on both sides of the equation. In this case, copper (Cu) is oxidized to Cu2+ and silver ions (Ag+) are reduced to silver metal (Ag). The correct balanced equation is:

Cu(s) + 2AgNO3(aq) → 2Ag(s) + Cu(NO3)2(aq)

The blue color of the solution is due to the formation of Cu2+ ions, which are blue in aqueous solution.

Quiz 4: Reactions in Aqueous Solutions

A piece of zinc metal was added to an aqueous solution of lead(II) nitrate. After some time it was observed that the zinc metal appeared to fall apart and a solid had accumulated at the bottom of the reaction vessel.Select the balanced chemical equation for this reaction.

If 145 grams of potassium nitrate were added to water to make 1,500 mL of solution. What would the molarity of the resulting solution be

During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with 1.0 M NaOH; 40. mL of the base were required to neutralize the sample. What is the molarity of the acid solution

During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with 1.0 M NaOH; 40. mL of the base were required to neutralize the sample. How many moles of acid are present in 2.0 liters of this unknown solution

Shown here is the balanced molecular equation that would occur between CaCl₂(aq) and Na₂CO₃(aq) . Which of the following is the balanced net ionic equation Molecular equation: CaCl₂(aq) + Na₂CO₃(aq) $\rarr$ CaCO₃(s) + 2NaCl(aq)

Shown here is the balanced molecular equation for the reaction that would occur between CuCl₂(aq) and Pb(s) . Which of the following, if any, shows the correctly balanced net ionic equation Molecular equation: CuCl₂(aq) + Pb(s) $\rarr$ Cu(s) + PbCl₂(s)

Which substance is acting as a Brønsted acid in the following reaction HSO₄^- + NH₄⁺ $\rarr$ H₂SO₄ + NH₃

During a titration the following data were collected. A 50.0 mL portion of an HCl solution was titrated with 0.500 M NaOH; 200. mL of the base was required to neutralize the sample. How many grams of HCl are present in 500. mL of this acid solution

H₂O is acting as a Brønsted acid in the following reaction. NH₃ + H₂O $\rarr$ NH₄⁺ + OH^-

What volume of concentrated nitric acid (15.0 M) is required to make 100. mL of a 3.0 M nitric acid solution

The solubility of Ba(NO₃) ₂ is 130.5 grams per liter at 0^$\circ$C. How many moles of dissolved salt are present in 4.0 liters of a saturated solution of Ba(NO₃) ₂ at 0ºC

What is the molar concentration of chloride ions in a solution prepared by mixing 100. mL of 2.0 M KCl with 50. mL of a 1.5 M CaCl₂ solution

Quiz 4: Reactions in Aqueous Solutions

A piece of zinc metal was added to an aqueous solution of lead(II) nitrate. After some time it was observed that the zinc metal appeared to fall apart and a solid had accumulated at the bottom of the reaction vessel.Select the balanced chemical equation for this reaction.

If 145 grams of potassium nitrate were added to water to make 1,500 mL of solution. What would the molarity of the resulting solution be

During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with 1.0 M NaOH; 40. mL of the base were required to neutralize the sample. What is the molarity of the acid solution

During a titration the following data were collected. A 10. mL portion of an unknown monoprotic acid solution was titrated with 1.0 M NaOH; 40. mL of the base were required to neutralize the sample. How many moles of acid are present in 2.0 liters of this unknown solution

Shown here is the balanced molecular equation that would occur between CaCl2(aq) and Na2CO3(aq) . Which of the following is the balanced net ionic equation Molecular equation: CaCl2(aq) + Na2CO3(aq) →\rarr→ CaCO3(s) + 2NaCl(aq)

Shown here is the balanced molecular equation for the reaction that would occur between CuCl2(aq) and Pb(s) . Which of the following, if any, shows the correctly balanced net ionic equation Molecular equation: CuCl2(aq) + Pb(s) →\rarr→ Cu(s) + PbCl2(s)

Which substance is acting as a Brønsted acid in the following reaction HSO4- + NH4+ →\rarr→ H2SO4 + NH3